Consequences for giving in, in a “cursed peril” kinda way. Relevant for here, imagine being followed around by a floating muffin. nobody else can see it and if you try to destroy it, it just reappears. Eating it, gives you a great feeling, enough for maybe even orgasming, but a single pound or kilo will be added to you, forever.
Alternatively, pleasing yourself, but finishing gives you the calories of a single muffin, unburnable.
I am into those kind of things, but for many other fetishes, stuff like shrinking, growing, shrinking of certain body parts from giving in, growing of those same body parts from giving in… basically, if a single moment of weakness can give a character permanent consequences like those and at first things may “not be that bad” or “maybe this is a blessing” until it gets too big/small/intense, I am into it.
Also, definitely hypno. that one reinapop vid is my fav for this fetish.
Just gonna add to this, the actions of someone else influencing transformation or behavior changes in me. Kinda into femdom and have a fantasy of something causing conflict resolving to add or subtract from the average strenght of one or the other gender. One victory for women, and men become slightly weaker all over. Two or three more, and stuff goes into an avalance, until some lower limit is reached, slowly.
The best way to display this would be some attempt to balance stuff slowly failing as the faux contests keep getting won by women as they get actively stronger while men get weaker, WHILE the contests are still happening.
Another one is a fit woman working to make a man… not fit. You know what I mean,
“look how many bags of fast food I can carry, bet you cant eat them all.”
“You gotta keep up, I can already lift 200 kilo. GET THERE”